Sectional electric heating element.



F. W. MOFFAT.

sEcTloNAL ELECTRIC HEATlNG ELEMENT.

APPLICATION FILED APR. I2. 1918.

1,27 6,096. PatentedAug.20,191s.

FREDERICK W. MOFFAT, OF WESTON, ONTARIO, CANADA.

SECTIONAL ELECTRIC HEATING ELEMENT.

Specification of Letters Patent.

Patented Aug. 20, 1918.

Application filed April 12, 1918. Serial No. 228,229.

To all ywhom. t may Concern.'

Be it known that I, FREDERICK IV. Moi- FAT, of the town of IVeston, in the county of York, Province of Ontario, Canada, have invented certain new and useful Improvements in Sectional Electric Heating Elements, of which the following is a specification.

This invention relates to heating elements specially adapted for heavy duty in hotels and restaurants and for other commercial work requiring large heating surface with three heats, and my obj ect is to devise means whereby an element can be built up of standard parts to any desired width and length to suit the requirements of any particular customer.

I attain my object by means of the constructions hereinafter described and illustrated in the accompanying drawings in which- Figure 1 is a plan view of part of an electric heating element built up according` to my invention;

Fig. 2 a section along the line ct--a in Fig. 1;

Fig. 3 an elevation of the outer face of one of the end members;

Fig. 4 a section on the line b-Z) looking toward the left hand side of Fig. 1.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

1 is a slab of refractory insulating material such as commonly employed in the manufacture of electric heating elements. This slab is provided in its upper surface with parallel grooves 2 extending through its ends. These grooves are preferably provided with the ribs 3 in their bottoms, as in the prior United States Patent No. 1195828 of August 22nd, 1916, granted to Lewis R. McClatchie, and also with lugs or project-ions 4 intended to hold down the resistance wires in the grooves. These features, however, form no part of the present invention.

5 is an end bar provided with holes adapted to aline with the grooves of the slab. 7 is an end bar also provided with holes 6 adapted to aline with the grooves of the slab. In each end bar are formed grooves S connecting alternate holes 6, said grooves passing alternately above and below alternate holes. The grooves in one bar are in staggered relationship to those in the other bar as will be seen particularly on reference to Figs. 3 and t of the drawings.

As the resistance wire is preferably formed in two separate circuits to give three heats and it is desired that the terminals shall be at one end, I employ an even number of the grooves S, and at least four, eight being the preferable number. As it is intended to employ a plurality of the slabs I arranged side by side as well as end to end, it is necessary to form parts of grooves S at each of one of the end bars. IVith the arrangement shown, these parts of grooves are located in the end bar 5, so that when a second end bar is placed end to end with it as illustrated in Fig. 1, a complete groove is formed. Through the grooves S the resistance wires are connected as illustrated.

Each end bar 5 has an outwardly extending flange 9 formed integral therewith, and through this iiange are bolted the terminals 10. One terminal at one end of the bar is intended to form a common terminal for both circuits of the resistance wire, while the other terminals form independent connections for the two circuits, as is common in the art.

Preferably a boss 11 is formed integral with the under side of the bar 5, through which the common terminal extends, and also a boss 12 through which both of the other terminals extend. Through the flange 9 and through the bosses are formed holes 13, through which the wires connecting with the resistance are led and connected with the terminals.

IVhen the wires are so connected, a lilling piece 1t is fitted over the flange 9 and against the side of the bar 5, so as to come Hush with the outer side of the iiange and top of the bar. All connections are then completely covered and the possibility of accidental short circuiting is avoided.

The slabs and end bars are fitted into a metal pan 15 of suitable dimensions to contain one or more slabs in length and one or more slabs in width plus the end bars. In the bottom of the pan is laid a quantity of kieselguhr or other heat insulating material and above this slabs of insulating material 16 of sutlicient thickness so that the upper sides of the slabs and end bars are just below the top of the pan. Holes are formed in the bottom of the pan for the passage of the bosses 11 and 12, so that the terminals are exposed below the pan for making the necessary connections with the switches. A metal plate 17 is fitted on and secured to the edges of thepan.

From the constructions described, it will be seen'that 1 have devised a construction which will enable a heating element of any desired size or capacity to be built up from standard parts, as any desired number of slabs 1 can be fitted end to end and -side to side, and the necessary number of end bars employed Ato correspond with the number of slabs which lie side by side. The only parts requiring to be made of different sizes are the pans in which the element is received and the metal plates 17 which forms the top of the element and on which the cooking is performed.

lVhat l claim as my invention is z- 1. In a sectional'electric heating element, the combination of a slab of -insulating material having parallel grooves for the reception of resistance wire formed in its upper surface and extending through its ends; and separate vend bars of insulating material in length substantially equal to the width of the slab, litted closely thereto, and having holes formed therein adapted to aline with the grooves of the slab, grooves being formed in the outer surface of each bar connecting alternate holes, said grooves passing alternately above and below alterf nate holes, and the grooves in one bar being in staggered relationship to those in the other bar.

2.V ln a sectional electric heating element,

the combination of a slab of insulating material having an even number of, and at least four, parallel grooves forthe receptionV of resistance'wire formed in its upper surface and extending through its ends; andv separate end bars of insulating material in length substantially equal to the width of the slab, tted closely'thereto, and having holes formed therein adapted to aline with theV grooves of the slab, grooves being formed in the outer surface of each bar connecting alternate holes, said grooves passing alternately above and below alternate holes, and the grooves in one bar being in staggered relationship to those in the other bar.

3. In a sectional electric heating element, the combination of a slab of insulating material having parallel grooves for the reception of resistance wire formed in its upper surface and extending through its ends; separate end bars of insulating material in length substantially equal to the width of the slab, fitted closely thereto, and having holes formed therein adapted to aline with the grooves of the slab, grooves being formed in the outer surface of each bar con-v necting alternate holes, said grooves passing alternately above and below alternate holes, and thegrooves in one bar being in staggered relationship to those in the other bar; an outwardly extending flange formed on one of the end bars below the holes; terminal posts secured through said flange, holes for the passage of the ends of the resistance wire being formed through said flange from top to bottom.

Ll. ln a sectional electric heating element, the combination of a slab of insulating material having parallel grooves for the reception of resistance wire formed in its upper surface and extending through its ends; separate end bars of insulating material having holes formed therein adapted to aline with the grooves of the slab, grooves being formed in the outer surface of each bar connecting alternate holes, said grooves ypassing alternately above and below alternate holes, and the grooves' in one bar being in staggered relationship to those in the other bar; an outwardly extending flange formed on lone of the end bars below the holes; terminal postssecured through said flange, holes for the passage of the ends of the resistanceV wire being formed through said flange from top to bottom; and a filling piece of insulating material adapted to t above the flange.

5. In a sectional electric heating element, the combination of a slab of insulating material having parallel grooves for the reception of resistance wire formed in its upper surface and extending through its ends; separate end bars of insulating material having holes formed therein adapted to aline with. the grooves of thevslab, grooves being formed in the outer surface of each vbar connecting alternate holes, said grooves passing alternately above and below alternate holes, and the grooves in one bar being in staggered relationship toV those in the other bar; an outwardly extending flange formed on one of the end bars below the holes; integral bosses depending from the flange; terminal posts secured through said flange and bosses, holes for the passageof the ends of the resistance wire being' formed through said flange and bosses from top to bottom.

6. In a sectional electric heating element, the combination of a slab of insulating ma-V terial having parallel grooves for the reception of resistance wire formed in its upperV surface and extending through its ends; separate end bars of insulating materialin length substantially equal to the width of the slab, fitted closely thereto, and having holesformed therein adapted to aline with the grooves of the slab, grooves being formed in the outer surface of each bar connecting alternate holes, said grooves passing alternately above and below alternate holes, and the grooves in one bar being in staggered relationship to those in the other bar; a metal pan into which the slab and bars are fitted; insulating material in the bottom of the pan on which the slab and bars rest; and a metal cover plate resting on the edges of the pan.

7. In a sectional electric heating element, the combination of a slab of insulating material having parallel grooves for the reception of resista-nce Wire formed in its upper surface and extending through its ends; separate en d bars of insulating material having holes formed therein adapted to aline with the grooves of the slab, grooves being formed in the outer surface of each bar connecting alternate holes, said grooves passing alternately above and below alternate holes, and the grooves in one bar being in staggered relationship to those in the other bar; an outwardly extending lange formed on one of the end bars belou7 the holes; integral bosses depending from the Hange; terminal posts secured through said flange and bosses, holes for the passage of the ends of the resistance Wire being formed through said iiange and bosses from top to bottom; a metal pan into which the slab and bars are fitted; insulating material in the bottom of the pan on which the slab and bars rest; and a metal cover plate resting on the edges of the pan, holes being formed in the bottom of the pan for the passage of the lower ends of the bosses aforesaid.

Signed at Toronto, Canada, this 3rd day of April, 1918.

FREDERICK lV. MOFFAT.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

